Heretofore, the procedure for detecting a carton on a typical packaging machine has occurred on the conveyor chain, just prior to the fill station, by microswitches operated by lever arms. The location of such switches and lever arms is in a high moisture area and such that they are very difficult to clean. A switch and lever arm are associated with each filler nozzle and if no carton is detected, a fill cycle will not occur for that particular nozzle. This is important because a carton may misfeed and, hence, not be inserted on the mandrel, resulting in an open carton slot in the conveyor. Therefore, a no-product/no-fill cycle should occur. A satisfactory electronic program control system is shown and described in U.S. Pat. No. 4,172,347, issued on Oct. 30, 1979, for filling individual containers in four equal portions as each progressively passes beneath four filler heads.